From left, German Chancellor Angela Merkel, Russian President Vladimir Putin, Turkey's President Recep Tayyip Erdogan and French President Emmanuel Macron attend a news conference following their summit on Syria, in Istanbul. Photo: AP

From left, German Chancellor Angela Merkel, Russian President Vladimir Putin, Turkey's President Recep Tayyip Erdogan and French President Emmanuel Macron attend a news conference following their summit on Syria, in Istanbul. Photo: AP